Mint plant named ‘Sambhav’

ABSTRACT

The present invention relates to a novel, insect tolerant, high yielding essential oil and menthol yielding mint plant named ‘Sambhav’, which is a cultivar of  Mentha arvensis  L.. The mint plant of the present invention has been developed as a result of planned experiments which devised a procedure for early selection of somaclonal variants at the in vitro stage of the variety of  Mentha arvensis .

Botanical designation: Mentha arvensis L.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The origin of the mint plant of the present application is a singlesomaclonal variant of cultivar ‘Himalaya’ (U.S. Plant Pat. No. 10,935).The present invention relates to a novel, insect tolerant, high yieldingessential oil and menthol yielding mint plant named ‘Sambhav’, which isderived from Mentha arvensis L.. The mint plant of the present inventionhas been developed as a result of planned experiments for thedevelopment of an insect tolerant mint plant with high oil and mentholyield which devised a procedure for early selection of somaclonalvariants at the in vitro stage variety of Mentha arvensis. The plant ofthe present invention can be propagated vegetatively by suckers and isgenetically stable for commercial cultivation. The plant type of thepresent invention is unique because it has an extra wide canopy andheight surpassing all existing varieties. This allows for bettersunlight capture and foliage production which ultimately produce highoil and menthol yield.

2. Description of Related Art

Mentha arvensis L. var piperescens Holmes (menthol or Japanese mint) isan industrial crop that is widely cultivated for its essential oil fromwhich menthol is purified by crystallization through freezing. Mentholand other terpenoids present in the dementholated oil of Mentha arvensisare used in the food, perfumery and pharmaceutical industries. In thevarietal improvement programme, the genetic alternations leading to theenhancement in the tolerance against pest and disease and improvement ofother characteristics which improve the yield and quality of essentialoil is most desirable. Insect tolerance is desired particularly againstSpilarctia obliqua in Mentha arvensis L., one of the most damaging pestsof mints in India. Since the mint plant is of considerable interest tothe industrial world, programs for the isolation of desirable cloneswith improved terpene accumulation and suitable agronomic traits arebeing pursued in several laboratories. However, due to the inherentproblem of seed setting in mints, conventional breeding programs areseverely hampered. In vitro high efficiency procedures for cell andcallus cultures and shoot regeneration from axillary buds and leafexplants have been reported in some species of the genus Mentha,especially the commercially important species M. piperata and M.spicata. However, in M. arvensis proliferation from limited explantssuch as nodes, terminal and axillary buds and distal segments of leafpetiole have relatively low levels of efficiency. There have beenattempts to develop new varieties or genotypes by alternative methodslike clonal selection, mutation breeding and somaclonal variation inmint plants (S. P. S. Khanuja, A. K. Shasany, S. Dhawan, S. Kumar, Rapidprocedure for isolating somaclones of altered genotypes in Menthaarvensis. J Med. Aroma. Plant Sci. 20 (1998) 359-361.). Applicants havereported high efficiency protocols for rapid detection and selectionprocedures for development of somaclonal variants through molecularapproaches in Mentha arvensis (S. P. S. Khanuja, A. K. Shasany, S.Dhawan, S. Kumar, Rapid procedure for isolating somaclones of alteredgenotypes in Mentha arvensis. J Med. Aroma. Plant Sci. 20 (1998)359-361). Applicants have also successfully defined the condition andmedia to restrict the emergence of somaclonal variation for stablemicropropagation purposes (A. K. Shasany, S. P. S. Khanuja, S. Dhawan,U. Yadav, S. Sharma, S. Kumar, High regenerative nature of Menthaarvensis internodes. Journal of Biosciences 23 (1998) 641646.).

SUMMARY OF THE INVENTION

For the present invention, Applicants utilize the already reportedprotocol (S. P. S. Khanuja, A. K. Shasany, S. Dhawan, S. Kumar, Rapidprocedure for isolating somaclones of altered genotypes in Menthaarvensis. J Med. Aroma. Plant Sci. 20 (1998) 359-361.) to generatecapture the somaclonal variations in larger frequencies. Applicants thenscreen the somaclones for their tolerance to Spilarctia obliqua by usinga novel method for rapid and dependable selection of tolerant clone(s)at the tissue culture stage. The somaclones that were determined to beinsect tolerant were then subjected to screening using instar larvae oflepidopteran insect pest Spilarctia obliqua.

The selected tolerant pants are then tested for their stability,essential oil content, menthol content and biomass yield. Consequently,the plant ‘Sambhav’ was selected for unmatchable vigor of shoots, highermenthol production and increased insect tolerance through fieldevaluation.

Accordingly, the invention provides a novel mint plant of Menthaarvensis named ‘Sambhav’, which is developed employing tissue culturetechniques, said plant of the present invention possessing the followingcombination of characteristics:

a. the plant is highly tolerant to foliage feeding insect pests,especially Spilarctia obliqua;

b. the plant possesses vigorous and rapid vegetative growth with highregenerability covering at least a 85 cm canopy area and a height of atleast 73.5 cm attained in a maximum of 100 days;

c. the plant has a distinct molecular profile by random amplifiedpolymorphic DNA (RAPD) using 20 OPJ primers and 20 MAP primers whichdistinguishes the plant from the other existing varieties,

d. the plant shows tolerance to leaf spots, rust and powdery mildew asin the parent variety ‘Himalaya’,

e. the plant has the follows characteristics: light greenish leaves,whitish flowers with a distinct morphology of a single main stem withbranches coming out of the lower nodes imparting a shape of up-side downopen filled umbrella to the canopy allowing equal distribution ofsunlight, thus prevents yellowing and fall of lower leaves;

f. the plant is able to produce the highest herbage when compare to theother control plants, and

g. the plant yields oil containing 75 to 80% menthol;

The plant of the present invention is developed through an unique, rapidin vitro screening method. This method is not limited to Menthaarvensis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows field views of the morphological features of the ‘Sambhav’plants at 70 days.

FIG. 2 shows field views of the morphological features of the ‘Sambhav’plants at 100 days.

FIG. 3 shows the rapid growth of the ‘Sambhav’ plant and its canopy at70 days.

FIG. 4 shows the rapid growth of the ‘Sambhav’ plant and its canopy at100 days.

FIG. 5 shows instar larvae infected individual clones of other plants incomparison with clone of ‘Sambhav’. Instar larvae is larvae that attacksmint plants.

FIG. 6 shows the Genetic similarity of the new clone ‘Sambhav’ withother varieties of Mentha arvensis.

BOTANICAL DESCRIPTION OF THE PLANT ‘SAMBHAV’

1. Genus: Mentha.

2. Species: arvensis L.

3. Family: Lamiaceae.

4. Common name: Japanese mint/corn mint/menthol mint.

5. Plant height: 73.5±3.27 cm.

6. Plant canopy: 85-90 cm.

A. Stem:

1. Shape.—Round to quadrangular, hard, woody.

2. Unit of branches (main, upper, middle, lower) Number ofFingers.—Right hand: 5. Left hand: 5.

2. Number of branches.—7 to 24.

3. Main branch.—18 to 37.

4. Upper branch ( 30 ^(th) node).—3 to 6.

5. Middle branch ( 20 ^(th) node).—3 to 8.

6. Lower branch ( 10 ^(th) node).—4 to 10.

7. Main branch (From lower to upper nodes in cm).—1.0 to 6.0.

B. Leaf:

Apex shape acute.—Base shape Attenuate.

Shape.—Lacerate.

Surface.—Hairy and rough.

Texture.—Moderately thick and rigid.

Margin.—Moderately deep serration (14 to 50 numbers).

Size.—Moderately broad.

Area.—16.1 cm² (the average leaf lamina area of 41 leaves of a singlebranch).

Length.—8.56±0.56 cm.

Width.—5.51±0.34 cm.

Petiole length.—1.7±0.17 cm.

Fragrance.—Methanol smell.

Vein.—Colour green (144A).

Colour of surface.—Light green (137B) for upper surface, Yellow green(139C) or lower surface.

Number of trichomes per leaf.—1280.

Trichome ratio (lower leaf/upper leaf).—3.10.

C. Time of flowering: April-May (60 to 70 days after planting firstflowering detected).

D. Lasting of blooms: Continue till harvesting (110 days afterplanting).

E. Flowers: Arranged in whorls surrounding the stem at the base oflateral leaves.

1. Size.—4.65 mm long.

2. Flower shape.—Tubular.

3. Inflorescence size.—Continues to grow as indefinite racemose.

4. Pedicel length.—1.1 to 2.5 mm.

5. Pedicel colour.—Yellow green (145C).

6. Calyx diameter.—1 mm, four fused.

7. Calyx colour.—Yellow green group (145B).

8. Corolla.—Purplish white, four, fused to a bell shaped corolla tube(76C-D), 3 to 4 mm long.

9. Anthers.—Four, ocidimetary, come out of the corolla tube.

10. Stigma.—Bifid, Purple (76A).

11. Colour of ovaries.—Yellow green group (151A).

12. Oil content in the fresh herb (%).—0.77 to 0.8.

13. Oil quality.—Menthol content (%): 75 to 80%. Congealing point: 2 to21° C.

Herbage (Shoot biomass (Q/100 m ²).—2.10

Bihar hairy caterpillar (Spilarctia obliqua) is a pest of a polyphagusnature which infects mint crops frequently in Terai and in the northernIndian plains. The infestation is sometimes so heavy and unmanageablethat it may lead to more than 80% complete loss of foliage andconsequently the oil yield proportionately. Therefore, it is desirableto explore the possibility of developing insect tolerant high yieldingclones of mint plants. The popular menthol producing mint plant variety‘Himalaya’ developed in 1996 by Central Institute of Medicine andAromatic Plants (hereinafter referred to as CIMAP) (U.S. Plant Pat. No.(10,935). This was the beginning of specific improvements in insecttolerance through generation of somaclonal variation whilesimultaneously looking for improved plant type with higher essential oiland menthol yields.

Encouraged by Applicants' own initial leads in the laboratory for rapiddetection and isolation of somaclonal variants by using the protocol (S.P. S. Khanuja, A. K. Shasany, S. Dhawan, S. Kumar, Rapid procedure forisolating somaclones of altered genotypes in Mentha arvensis. J Med.Aroma. Plant Sci. 20 (1998) 359-361), Applicants generated 3000independent somaclones. These clones were subjected to detection ofmolecular variation at the tissue culture stage through RAPD profiling.The DNA was isolated from 40 mg of leaf tissue and Polymerase chainreactions (PCRs) were carried out in 25 μl volume in a reaction tubecontaining 25 ng of DNA, 0.2 unit of Taq DNA polymerase, 100 pl each ofdNTPs, 1.5 mM MgC₁₂ and 5 p mol of decanucleotide primers. Theamplifications were carried out using a thermal cycler (MJ Research,USA). The amplified products were loaded in 1.2% agarose gel containing0.5 μg ml⁻¹ of ethidium bromide and photographed by Polaroid system.Twelve decamer primers having the Sequence ID NOs 1-12 AAATCGGAGC (SEQID NO:1), GTCCTACTCG (SEQ ID NO: 2), GTCCTTAGCG (SEQ ID NO:3),TGCGCGATCG (SEQ ID NO:4), AACGTACGCG (SEQ ID NO:5), GCACGCCGGA (SEQ IDNO:6), CACCCTGCGC (SEQ ID NO:7), CTATCGCCGC (SEQ ID NO:8), CGGGATCCGC(SEQ ID NO:9), GCGAATTCCG (SEQ ID NO: 10), CCCTGCAGGC (SEQ ID NO: 11),CCAAGCTTGC (SEQ ID NO:12) were used to analyze all the in vitroregenerated clones. Out of 3000 regenerated clones, 245 showedvariations at the DNA level in the RAPD profiles compared to the controlplant “Himalaya”.

The individual molecular variants selected through the RAPD analysis ofsomaclones were then subjected to screening against the larvae oflepidopteran insect pest Spilarctia obliqua.

For this purpose, a new strategy was devised by subjecting the in vitrogrowing clones to attack by actively feeding 3^(rd) instar larvae. Thelarvae were released right in the culture tubes containing individualclones on the rooting medium (FIG. 5). Most of the shoots of the cloneswere eaten away by these larvae within 2-3 days. However, three clonesshowed the least feeding by the larvae. In these tubes, only initialbites could be observed and nonfeeding was also conspicuous by typicalsymptoms of stalled growth in the starved larvae. These larvae were thentransferred to other clone tubes, where they resumed feeding. This ledApplicants to believe that the three clones must have somecharacteristics not liked by the feeding larvae. So Applicants againconfirmed this by releasing another set of actively feeding 4^(th)instar larvae into the tubes containing these three identified clones.This process was repeated three times and each time, the larvae showednon-preference to the clones and stopped feeding.

Applicants then hardened these three “insect-non-preferred” clonesnamely, CIMAP/GRB 1-06, ‘Sambhav’ and CIMAP/GRB 5-15 and transferredthem to the glasshouse in pots. Among these three clones, ‘Sambhav’showed growth characteristics that were much higher in height and shootproliferation. ‘Sambhav’ (This GRB) was multiplied in vitro frominterodal explants through stable micropropagation protocol developed inthe laboratory (A. K. Shasany, S. P. S. Khanuja, S. Dhawan, U. Yadav, S.Sharma, S. Kumar, High regenerative nature of Mentha arvensisinternodes. Journal of Biosciences. 23 (1998) 641-646.) for geneticuniformity into about 1000 plantlets. Randomly 100 regenerated shootsfrom the clone were tested for variation in their profiles using theabove described 12 random primers. Complete uniformity was observedamong these clones without any variation from the control mother plant‘Sambhav’ but the profiles were clearly distinct from other mintvarieties including ‘Himalaya’.

Breeding History

The plant ‘Sambhav’ can be propagated vegetatively through suckers forcultivation. The plant was developed by performing the RAPD analysis,selecting different somaclones followed by force feeding by insect toscreen for insect tolerance character. The selected plant was grown inthe glass house and the suckers obtained were field planted formultiplication. The suckers from the multiplication plots were taken forplanting in the main field for field trials. Replicated field trialswere conducted following normal agromonic practices by plantingmultiplied suckers in January 1998 and January 1999 in RBD fashion.Different growth and yield characteristics were recorded. For fieldtrials, 10 m×10 m plots were prepared by adding only FYM 1.5 ton per ha.The field experiments were carried out in the farm field of CIMAP.

The seeds and fruits were not checked as the plant is propagatedvegetatively through suckers.

The plants of the present invention was described after 100 days ofplanting during the month of May when the maximum temperature remainedbetween 32 to 42° C. and the minimum temperature remained between 25 and32° C.

The overall objective of the present invention was not only to developinsect tolerant genotypes but to simultaneously also have a better planttype with high menthol content and herbage yield for betterproductivity. So, the plant of present invention was tested in the fieldfor oil yield, menthol content and herbage production against thechecks. Replicated field trials were conducted following normalagronomic practices by planting multiplied suckers in January, 1998 andJanuary, 1999 for 2 consecutive years in RBD fashion and diffent growthand yield characteristics were recorded (Table. 1). For field trials, 10m×10 m plots were prepared by adding only FYM 1.5 ton per ha.Astonishingly, the ‘Sambhav’ was able to out-compete all existingvarieties in its rate of growth. It was so rapidly growing that it couldcover the inter-row spacing of 80 cm completely within a period of90-100 days, which was not the case for the other control varietiestaken (FIG. # 2). The plant canopy covered a space of 85 to 90 cm in 110days in comparison to Himalaya(62-70 cm), Shivalik (50-56 cm)(unpatented), Gomti (70-75) (unpatented); Kosi (65-72) U.S. Plant Pat.No. 12,426, Kalka (40-60 cm) (unpatented) MAS-1(40-50 cm) (unpatented).This was the most desirable advantage to the plant because it producedthe highest amount of oil and menthol.

Natural infestation of Spilarctia obliqua in the field absentinsecticidal spray was noted in both the 1998 and 1999 crop stands. Theclone ‘Sambhav’ had less than 10% leaf damage compared to 86% in thecase of Gomti, 58% in Himalaya, 50% in Kosi in 1998. A similar trend wasalso recorded in 1999 when leaf damage was 70%, 50% and 46% for Gomti,Himalaya and Kosi respectively, compared to 6% in case of GRB ‘Sambhav’.The plant of the present invention also produced the highest amount ofessential oil per unit area in comparison to the other control plants inboth successive yield trials. The total menthol yield consequently, wasthe highest due to more oil and herbage yield (Table 1). The plant wasnamed ‘Sambhav’ (means “Possible”) because the expression of itsgenotype made this a rare but most desirable combination of traits.

Thus, the plant of the present invention ‘Sambhav’ has a very hightolerance to Spilarctia obliqua attack, high growth rate andregenerability and produces the highest total herbage, oil and mentholyield per unit area in comparison to the other control plants andthereby being a unique and novel genotype which can be exploited forcommercial cultivation superior to other available mint varieties formenthol production.

TABLE 1 Comparative growth and yield characteristics of plant ofinvention “Sambhav” (GRB 2-18) in relation to the existing Japanese mintvarieties Property Himalaya Shivalik MAS-1 Kalka Plant height 60.9 + 6.268.25 + 3.4  43.2 + 1.1 51.6 + 2.7  (cm) Canopy (cm) 62-70 50-56 40-5040-60 Leaf number 40.2 + 4.2 49.6 + 4.8 40.0 + 1.4  38 + 2.0 Branchlength 40.4 + 6.8 44.2 + 8.7 36.6 + 9.0  45 + 9.7 Branch number 29.2 +4.0 22.4 + 1.7 13.6 + 1.7 27.2 + 1.1  Leaf length  7.1 + 0.5  7.3 + 0.3 7.5 + 1.0 7.4 + 0.8 Leaf breadth  4.5 + 0.2  5.0 + 0.2  3.8 + 0.5 4.0 +0.3 Petiole length 1.75 + 0.3 1.40 + 0.1  1.6 + 0.5 1.5 + 0.5 Oil % 0.70.5 0.5 0.8 Menthol % 80 77 88 82 Herbage yield 1.25 0.75 0.50 0.80 (Qper 100 m²) Oil yield (Kg 0.85 0.35 0.27 0.64 per 100 m²) Property GomtiKosi Sambhav Plant height (cm) 74.2 + 7.3  66.2 + 3.1 73.5 + 3.3 Canopy(cm) 70-75 65-72 85-90 Leaf number 46.0 + 2.8  50.4 + 3.8 44.2 + 2.2Branch length 58.4 + 14.6 52.0 + 5.7 50.1 + 8.8 Branch number 28.4 +2.9  30.4 + 1.7 35.1 + 2.8 Leaf length 7.7 + 0.6 7.40 + 0.7  8.6 + 0.6Leaf breadth 4.7 + 0.2 4.60 + 0.5 5.50 + 0.3 Petiole length 1.4 + 0.1 1.4 + 0.3 1.70 + 0.2 Oil % 0.5 0.8 0.8 Menthol % 73 76 77 Herbage yield1.60 1.70 2.10 (Q per 100 m²) Oil yield (Kg per 0.83 1.42 1.61 100 m²)

TABLE 2 Comparison of “Sambhav” with other existing varieties of thesame botanical and market class of Mentha arvensis Character cv.MAS-1cv.Kalka cv.Shivalik 1. Leaf:stem ratio 1.2 1.0 0.8 2. Stem colour Uppergreen GREEN Green (141B) (141C), lower (141C), lower lower pig-pigmented red pigmented red mented red purple (71B) purple (71B) purple(71B) Stiffness Hard Hard Woody Thickness at 5^(th) 6.8 3.6 10.0 internode (mm) 3. Leaf Colour Green (139C) Green (139C) Green (138A)Length (cm)  6.46 6.7 5.2 Width (cm) 2.3 2.4 2.8 Area (cm²) 8.2 8.710.1  4. Petiole length 1.1 1.2 0.6 (cm) 5. Flower colour WhitishWhitish Whitish 6. Flower length  3.72  3.48  4.66 (mm) 7. Calyx colourGreen (143B) Green (143B) Green (141B) with red purple with red purplestreaks (71B) streaks (71B) 8. Stigma colour White White Purplish (71C)9. Disease incidence to Rust Tolerant Resistant Susceptible Alternaria —Resistant Susceptible leaf blight Corynespora Susceptible TolerantSusceptible leaf spot Powdery Susceptible Susceptible Tolerant mildew10. Pest infestation Spilarctia obliqua Susceptible SusceptibleSusceptible Character cv.Gomti cv.Himalaya cv.Sambhav 1. Leaf:stem ratio1.0 1.5 1.7 2. Stem colour Green (143B) Green (143C) Green (144A) lowerlower lower pigmented purplish (70A) purplish (59B) purple (77A)Stiffness Woody Hard Woody Thickness at 5^(th) 7.9 8.0 10.0 internode(mm) 3. Leaf Colour Green (138A) Green (138B) Green (137B) Length (cm)6.4 6.2 8.6 Width (cm) 3.1 3.6 5.1 Area (cm²) 13.3  15.4  16.1  4.Petiole length 0.7 1.5 1.7 (cm) 5. Flower colour Whitish Pinkish whitePurplish white (76C) 6. Flower length  4.74  3.72  4.65 (mm) 7. Calyxcolour Green (141B) Green (143C) Green (145B) 8. Stigma colour Purplish(71C) White Purple (76A) 9. Disease incidence to Rust SusceptibleResistant Resistant Alternaria Susceptible Resistant Resistant leafblight Corynespora Susceptible Tolerant Tolerant leaf spot PowderyTolerant Tolerant Tolerant mildew 10. Pest infestation Spilarctiaobliqua Highly Susceptible Tolerant Susceptible

The plant genotype ‘Sambhav’ of the present invention is a herbaceousperennial with a single tall upright stem possessing several lateralbranches coming out from the lower nodes laterally rising in a fashionto give a shape of an open filled umbrella turned upside down. Thisspecial arrangement of branches facilitates the distribution of thecaptured sunlight equally to all the leaves and hence avoids shading,reducing lower leaf fall, which prevents economic loss to the plant. Thechromosome number of the plant is 2n=96. The colour codes are inaccordance with the “R.H.S. colour chart” published by The RoyalHorticultural Society, 80 Vincent Square, London SW1P 2PE, 1995.

Evidence of uniformity and stability

No variants of any kind (morphological or molecular) has been observedsince 1997 indicating the stability and uniformity of the genotype.Further, the comparative herbage and oil yields of ‘Sambhav’ weresignificantly higher in comparison to other varieties/genotypes indifferent years and seasons. Due to vigorous vegetative growth thisgenotype can be harvested earlier without reducing the yield of herbage,oil or menthol. The traits of insect tolerance against S. obliqua isunprecedented and stable.

Statement of distinction

The genotype ‘Sambhav’ possesses a very high level of insect toleranceagainst leaf damage by S. obliqua larvae, which is unique andunprecedented by any known variety. Additionally, it has a distinctcanopy of one straight main stem with many lower branches arranged likean open filled umbrella turned upside down which is characteristic tothis genotype only. The genotype of the present invention has thehighest biomass and highest oil yield unit area in comparison to others.The total menthol yield of the new genotype is higher per unit area incomparison to other genotypes. Its genetic make up is distinct in termsof the DNA profile.

Randomly Amplified Polymorphic DNA analysis

The RAPD profiles of the plant ‘Sambhav’ establish its distinct identityas completely different from the parent plant ‘Himalaya’ as well as theknown released varieties. The plant of the present invention wasdeveloped by screening molecular variants among somaclones alreadydifferentiated as distinct, unique and novel at the DNA level. The plantof the present invention has desirable morphological and economicaltraits in a rare unmatchable combination and is available only byApplicants in CIMAP. No variation in the RAPD patterns was observed inthe analysis of the micropropagated as well as field raised populationin successive generations indicating the stability of the genotype. The20 MAP primers (MAP 01 to MAP 20) with the Sequenc ID NOs 1-20AAATCGGAGC (SEQ ID NO:1), GTCCTACTCG (SEQ ID NO:2), GTCCTTAGCG (SEQ IDNO:3), TGCGCGATCG (SEQ ID NO:4), AACGTACGCG (SEQ ID NO:5), GCACGCCGGA(SEQ ID NO:6), CACCCTGCGC (SEQ ID NO:7), CTATCGCCGC (SEQ ID NO:8),CGGGATCCGC (SEQ ID NO:9), GCGAATTCCG (SEQ ID NO:10), CCCTGCAGGC (SEQ IDNO:11), CCAAGCTTGC (SEQ ID NO:12), GTGCAATGAG (SEQ ID NO:13), AGGATACGTG(SEQ ID NO:14) AAGATAGCGG (SEQ ID NO:15), GGATCTGAAC (SEQ ID NO:16),TTGTCTCAGG (SEQ ID NO:17), CATCCCGAAC (SEQ ID NO:18), GGACTCCACG (SEQ IDNO:19), AGCCTGACGC (SEQ ID NO:20) and 20 OPJ primers (OperonTechnologies Inc, USA) were used for the analysis and similarity indiceswere computed to generate a similarity matrix among existing varietiesand the plant ‘Sambhav’ (Table 3) The OPJ primers (01 to 20) wereobtained from Operon technologies, USA. The MAP primers were used todevelop a unique and distinct RAPD profile of the Plant.

TABLE 3 Similarity indices of different control plants analyzed incomparison to ‘Sambhav’ Gomti Himalaya Kosi MAS-1 Kalka Shivalik Sambhav1.00 0.90 1.00 0.89 0.94 1.00 0.91 0.92 0.92 1.00 0.85 0.88 0.85 0.891.00 0.92 0.93 0.91 0.90 0.87 1.00 0.87 0.73 0.78 0.82 0.83 0.84 1.00

TABLE 4 Genetic similarity of the new clone ‘Sambhav’ with othervarieties of Mentha arvensis.

From RAPD analysis, the profiles were studied and similarity indiceswere calculated which were put into a matrix. This matrix was used toproduce a graphic phenogram by means of UPGMA (unweighted pair groupmethod with arithmetic average) cluster analysis (FIG. 1). Asrepresented in the phenogram the clone of the invention is quitedifferent from the other varieties. The diversity of the genotype of theplant of invention ‘Sambhav’ is 13%, 28%, 22%, 18%, 17% and 16% from thevarieties Gomti, Himalaya, Kosi, MAS-1, Kalka and Shivalik. The highestdifference in terms of polymorphic profiles was observed for thegenotype of the invention with the parent plant ‘Himalaya’ from which itwas developed as a somaclone. The plant genotype of the invention‘Sambhav’ was most similar in terms of polymorphism with Gomti. In totalthe distinctiveness of the clone in RAPD profiles was established astotal polymorphism detected.

Comparison of Sambhav with the check varieties

The new genotype ‘Sambhav’ was so rapidly growing that it could coverthe inter-row spacing of 80 cm completely within a period of 90-100days, which was not the case of other control varieties taken (FIG. #2). The plant canopy covered a space of 85 to 90 cm in 110 days incomparison to Himalaya (62-70 cm), Shivalik (50-56 cm), Gomti (70-75),Kosi (65-72), Kalka (40-60 cm) and MAS-1_(40-50 cm). The herbage yieldof the plant 2.8 Q per 100 m² against 1.25, 0.75, 0.50, 0.80, 1.60, 1.70for Himalaya, Shivalik, MAS-1, Kalka, Gomti and Kosi. Similarly the oilyield was highest (0.8%) in case of the genotype. The genotype thoughhas less menthol percentage, when the total menthol yield per 100 m² isestimated by converting the total oil yield per 100 m² against thementhol percentage (77×1.61/100) and it comes to 1.24 kg, which is muchhigher than other varieties. The menthol yield values for othervarieties are 0.68, 0.27, 0.24, 0.52, 0.60,1.08 kg per 100 m² forHimalaya, Shivalik, MAS-1, Kalka, Gomti and Kosi respectively. This wasthe most desirable economical advantage to the plant with commercialvalue as it produced highest amount of herbage when compared to theother control plants and ultimately the oil and menthol per unit area incomparison to other genotypes while being the most tolerant to insectpest attack.

20 1 10 DNA Artificial Sequence MAP Primer 1 aaatcggagc 10 2 10 DNAArtificial Sequence MAP Primer 2 gtcctactcg 10 3 10 DNA ArtificialSequence MAP Primer 3 gtccttagcg 10 4 10 DNA Artificial Sequence MAPPrimer 4 tgcgcgatcg 10 5 10 DNA Artificial Sequence MAP Primer 5aacgtacgcg 10 6 10 DNA Artificial Sequence MAP Primer 6 gcacgccgga 10 710 DNA Artificial Sequence MAP Primer 7 caccctgcgc 10 8 10 DNAArtificial Sequence MAP Primer 8 ctatcgccgc 10 9 10 DNA ArtificialSequence MAP Primer 9 cgggatccgc 10 10 10 DNA Artificial Sequence MAPPrimer 10 gcgaattccg 10 11 10 DNA Artificial Sequence MAP Primer 11ccctgcaggc 10 12 10 DNA Artificial Sequence MAP Primer 12 ccaagcttgc 1013 10 DNA Artificial Sequence MAP Primer 13 gtgcaatgag 10 14 10 DNAArtificial Sequence MAP Primer 14 aggatacgtg 10 15 10 DNA ArtificialSequence MAP Primer 15 aagatagcgg 10 16 10 DNA Artificial Sequence MAPPrimer 16 ggatctgaac 10 17 10 DNA Artificial Sequence MAP Primer 17ttgtctcagg 10 18 10 DNA Artificial Sequence MAP Primer 18 catcccgaac 1019 10 DNA Artificial Sequence MAP Primer 19 ggactccacg 10 20 10 DNAArtificial Sequence MAP Primer 20 agcctgacgc 10

I claim:
 1. A new and distinct variety of Mentha arvensis plant, asherein illustrated and described.